Aluminum Alloy Guide for Die Casting
Aluminum is the workhorse of high-pressure die casting (HPDC) thanks to its low density, good castability and corrosion resistance. This guide compares the most common alloys.
Why aluminum for die casting?
- Lightweight — about one-third the density of steel, ideal for automotive and electronics lightweighting.
- Good fluidity — fills thin, complex tooling at high production rates.
- Corrosion resistant — forms a passive oxide layer; often usable as-cast.
- Recyclable — high scrap value and low remelting energy.
Common HPDC aluminum alloys
Representative values (confirm against current alloy datasheets). Cost index is relative to A380 = 1.00.
| Alloy | Density (g/cm³) | Tensile (MPa) | Thermal λ (W/m·K) | Cost index | Notes |
|---|---|---|---|---|---|
| A380 | 2.71 | 324 | 96 | 1.00 | General-purpose workhorse |
| A383 | 2.70 | 310 | 92 | 1.02 | Improved die filling vs A380 |
| A360 | 2.68 | 317 | 105 | 1.08 | Better corrosion & pressure tightness |
| A413 | 2.66 | 296 | 100 | 1.05 | High fluidity, thin walls |
| A384 | 2.74 | 310 | 90 | 1.06 | Higher ductility variant |
| A390 | 2.73 | 280 | 120 | 1.12 | High-Si, wear-resistant (pistons) |
How to choose
Prioritise strength & stiffness
- A380 / A384 give the highest tensile among common HPDC alloys.
- Keep wall sections uniform to avoid stress concentrators.
Prioritise thermal performance
- A360 and A390 lead on thermal conductivity — heatsinks, enclosures.
- A390 also offers excellent wear resistance.
Prioritise cost & castability
- A380 remains the cost-effective default.
- A413 / A360 suit very thin, complex walls.